It is quite easy:
Every station with less the 1 % presence in your band watching on the average band population is DX for you.
So when you are a W.. /MM station and able to work Peter and Paul Rock PY0S which is within 2 miles of your ship, its DX.
Sure it is. Push that pile up of the whole planet under your signal as a last come first serve action. And give them a real 5nn. Add that it is a real report, because 5nn is a lie in general, so you have to mention explicitly that its real 599.
Or guys that are planning to end their life by jumping for a train, or down from a roof, they can start to operate from North Korea.
North Korea P5, for example, doesn't allow any of its citizens to own amateur radio equipment or disseminate information outside the country by any means. I believe the punishment is death for breaking that law. So it is a nicer method then suicide as your last do-it-yourself-activity. No chance to end up in a wheelchair due to lack of experience in this field.
When you work on 30 GHz , where you can watch the eternal noise fields, the heaven for all radio amateurs, dx is your neighbour ham who transmits CW there, according to the definition.
Bob the sole genuine PAoBLAH